<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>myTrim</title>
</head>
<body>
<script>
    String.prototype.myTrim = function () {
        var str = this
        return str.replace(/^\s+|\s+$/g, "")
    }

    var str = "                                   mystr  "
    console.log("=======================")
    console.log(str)
    console.log("=======================");
    console.log("trim", str.trim())
    console.log("=======================");
    console.log("myTrim", str.myTrim())

</script>
</body>
</html>
